gistfile1.txt

grammar Where	
	rule expression
		'(' space expression space ')' / conjoined
	end
	
	rule conjoined
		primary space conjunction space expression / primary
	end
	
	rule conjunction
		'and'* / 'or'*
	end
	
	rule primary
		'(' space primary space ')' / condition
	end
	
  rule condition
		dimension space operator space value
  end
	
	rule operator
		(eq / neq / lte / lt / gte / gt)
	end
	
	rule value
		(real_value / whole_value / string_value)
	end
	
	rule eq
	  '='
	end
	
	rule neq
	  '<>'
	end
	
	rule lte
	  '<='
	end
	
	rule gte
	  '>='
	end
	
	rule lt
		'<'
	end
	
	rule gt
	  '>'
	end

  rule real_value
  	whole_value '.' [0-9]*
  end

  rule whole_value
    [1-9] [0-9]*
  end

  rule string_value
 		"'" (!"'" .)* "'"
  end

  rule dimension
		[\w\_0-9]+
	end
	
	rule space
		' '*
	end
end